1. FIELD OF THE INVENTION:
This invention relates to aids and methods useful in converting miles per hour readings into kilometers per hour readings.
2. DESCRIPTION OF THE PRIOR ART:
Barring changes in the plans of the Federal Highway Administration, conversion to the metric system on the highways of the United States will come about in the near future. Since highways signs will be changed from miles per hour to kilometers per hour, the motorist will need some quick and accurate means for converting his car speedometer from miles per hour readings to kilometers per hour. It is expected that after the changeover, new cars will show speedometer readings in both miles and kilometers per hour until the new system is implemented. Thereafter, it is expected that only kilometer per hour speedometers will be produced. Those who own older cars will thus be faced with an immediate conversion problem.
One approach thus far has been to have a conversion chart positioned adjacent the transparent speedometer front cover so that the driver can view his car speed on the mile per hour scale and quickly look at the adjacent chart to obtain his kilometer per hour conversion reading. This approach, however, is distracting to the driver and requires his removing his eyes and attention from the highway and traffic.
Another approach conceived is that of glueing little arrows to the speedometer front thereby giving three or four converted readings. These readings would mark the most widely employed speed limits, e.g., 55 m.p.h.; 45 m.p.h.; 35 m.p.h.; and 25 m.p.h. Such a system of marking would give the driver a general feeling about the speed he is driving. This is an improvement over the previous approach, however, it does not give the driver a constant reading which is most favorable.
British Pat. No. 1,251,425 teaches a scale conversion sheet which is applied to the speedometer front cover by adhesion. The transparent nature of the sheet enables the speedometer to be read in either the original or the new kilometer scale without mathematical conversion. The sheet is of a size and shape corresponding to the transparent front of a particular speedometer and has clear adhesive provided on one surface protected by a removable backing sheet. Even this approach is deemed impractical however considering the number of different shapes involved in automobile speedometers on today's market.
With the foregoing in mind, there is obviously an immediate need for a simple, interchangeable, inexpensive kit and method for converting mile per hour speedometer readings to kilometer per hour readings.